[PATCH v5 6/8] kernel/jump_label: abstract jump_entry member accessors

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

In preparation of allowing architectures to use relative references
in jump_label entries [which can dramatically reduce the memory
footprint], introduce abstractions for references to the 'code' and
'key' members of struct jump_entry.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/include/asm/jump_label.h     | 27 ++++++++++++++
 arch/arm64/include/asm/jump_label.h   | 27 ++++++++++++++
 arch/mips/include/asm/jump_label.h    | 27 ++++++++++++++
 arch/powerpc/include/asm/jump_label.h | 27 ++++++++++++++
 arch/s390/include/asm/jump_label.h    | 20 +++++++++++
 arch/sparc/include/asm/jump_label.h   | 27 ++++++++++++++
 arch/tile/include/asm/jump_label.h    | 27 ++++++++++++++
 arch/x86/include/asm/jump_label.h     | 27 ++++++++++++++
 kernel/jump_label.c                   | 38 +++++++++-----------
 9 files changed, 225 insertions(+), 22 deletions(-)

diff --git a/arch/arm/include/asm/jump_label.h 
b/arch/arm/include/asm/jump_label.h
index e12d7d096fc0..7b05b404063a 100644
--- a/arch/arm/include/asm/jump_label.h
+++ b/arch/arm/include/asm/jump_label.h
@@ -45,5 +45,32 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/arm64/include/asm/jump_label.h 
b/arch/arm64/include/asm/jump_label.h
index 1b5e0e843c3a..9d6e46355c89 100644
--- a/arch/arm64/include/asm/jump_label.h
+++ b/arch/arm64/include/asm/jump_label.h
@@ -62,5 +62,32 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #endif  /* __ASSEMBLY__ */
 #endif /* __ASM_JUMP_LABEL_H */
diff --git a/arch/mips/include/asm/jump_label.h 
b/arch/mips/include/asm/jump_label.h
index e77672539e8e..70df9293dc49 100644
--- a/arch/mips/include/asm/jump_label.h
+++ b/arch/mips/include/asm/jump_label.h
@@ -66,5 +66,32 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #endif  /* __ASSEMBLY__ */
 #endif /* _ASM_MIPS_JUMP_LABEL_H */
diff --git a/arch/powerpc/include/asm/jump_label.h 
b/arch/powerpc/include/asm/jump_label.h
index 9a287e0ac8b1..412b2699c9f6 100644
--- a/arch/powerpc/include/asm/jump_label.h
+++ b/arch/powerpc/include/asm/jump_label.h
@@ -59,6 +59,33 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #else
 #define ARCH_STATIC_BRANCH(LABEL, KEY)         \
 1098:  nop;                                    \
diff --git a/arch/s390/include/asm/jump_label.h 
b/arch/s390/include/asm/jump_label.h
index 40f651292aa7..3d4a08e9514b 100644
--- a/arch/s390/include/asm/jump_label.h
+++ b/arch/s390/include/asm/jump_label.h
@@ -50,5 +50,25 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline jump_label_t jump_entry_key(const struct jump_entry *entry)
+{
+       return entry->key;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
 #endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/sparc/include/asm/jump_label.h 
b/arch/sparc/include/asm/jump_label.h
index 94eb529dcb77..18e893687f7c 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -48,5 +48,32 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #endif  /* __ASSEMBLY__ */
 #endif
diff --git a/arch/tile/include/asm/jump_label.h 
b/arch/tile/include/asm/jump_label.h
index cde7573f397b..86acaa6ff33d 100644
--- a/arch/tile/include/asm/jump_label.h
+++ b/arch/tile/include/asm/jump_label.h
@@ -55,4 +55,31 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #endif /* _ASM_TILE_JUMP_LABEL_H */
diff --git a/arch/x86/include/asm/jump_label.h 
b/arch/x86/include/asm/jump_label.h
index 8c0de4282659..009ff2699d07 100644
--- a/arch/x86/include/asm/jump_label.h
+++ b/arch/x86/include/asm/jump_label.h
@@ -74,6 +74,33 @@ struct jump_entry {
        jump_label_t key;
 };
 
+static inline jump_label_t jump_entry_code(const struct jump_entry *entry)
+{
+       return entry->code;
+}
+
+static inline struct static_key *jump_entry_key(const struct jump_entry *entry)
+{
+       return (struct static_key *)((unsigned long)entry->key & ~1UL);
+}
+
+static inline bool jump_entry_is_branch(const struct jump_entry *entry)
+{
+       return (unsigned long)entry->key & 1UL;
+}
+
+static inline bool jump_entry_is_module_init(const struct jump_entry *entry)
+{
+       return entry->code == 0;
+}
+
+static inline void jump_entry_set_module_init(struct jump_entry *entry)
+{
+       entry->code = 0;
+}
+
+#define jump_label_swap                NULL
+
 #else  /* __ASSEMBLY__ */
 
 .macro STATIC_JUMP_IF_TRUE target, key, def
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 8594d24e4adc..baed094ab8d1 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -37,10 +37,12 @@ static int jump_label_cmp(const void *a, const void *b)
        const struct jump_entry *jea = a;
        const struct jump_entry *jeb = b;
 
-       if (jea->key < jeb->key)
+       if ((unsigned long)jump_entry_key(jea) <
+           (unsigned long)jump_entry_key(jeb))
                return -1;
 
-       if (jea->key > jeb->key)
+       if ((unsigned long)jump_entry_key(jea) >
+           (unsigned long)jump_entry_key(jeb))
                return 1;
 
        return 0;
@@ -53,7 +55,8 @@ jump_label_sort_entries(struct jump_entry *start, struct 
jump_entry *stop)
 
        size = (((unsigned long)stop - (unsigned long)start)
                                        / sizeof(struct jump_entry));
-       sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL);
+       sort(start, size, sizeof(struct jump_entry), jump_label_cmp,
+            jump_label_swap);
 }
 
 static void jump_label_update(struct static_key *key);
@@ -254,8 +257,8 @@ EXPORT_SYMBOL_GPL(jump_label_rate_limit);
 
 static int addr_conflict(struct jump_entry *entry, void *start, void *end)
 {
-       if (entry->code <= (unsigned long)end &&
-               entry->code + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
+       if (jump_entry_code(entry) <= (unsigned long)end &&
+           jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE > (unsigned long)start)
                return 1;
 
        return 0;
@@ -314,16 +317,6 @@ static inline void static_key_set_linked(struct static_key 
*key)
        key->type |= JUMP_TYPE_LINKED;
 }
 
-static inline struct static_key *jump_entry_key(struct jump_entry *entry)
-{
-       return (struct static_key *)((unsigned long)entry->key & ~1UL);
-}
-
-static bool jump_entry_branch(struct jump_entry *entry)
-{
-       return (unsigned long)entry->key & 1UL;
-}
-
 /***
  * A 'struct static_key' uses a union such that it either points directly
  * to a table of 'struct jump_entry' or to a linked list of modules which in
@@ -348,7 +341,7 @@ static enum jump_label_type jump_label_type(struct 
jump_entry *entry)
 {
        struct static_key *key = jump_entry_key(entry);
        bool enabled = static_key_enabled(key);
-       bool branch = jump_entry_branch(entry);
+       bool branch = jump_entry_is_branch(entry);
 
        /* See the comment in linux/jump_label.h */
        return enabled ^ branch;
@@ -364,7 +357,8 @@ static void __jump_label_update(struct static_key *key,
                 * kernel_text_address() verifies we are not in core kernel
                 * init code, see jump_label_invalidate_module_init().
                 */
-               if (entry->code && kernel_text_address(entry->code))
+               if (jump_entry_is_module_init(entry) &&
+                   kernel_text_address(jump_entry_code(entry)))
                        arch_jump_label_transform(entry, 
jump_label_type(entry));
        }
 }
@@ -417,7 +411,7 @@ static enum jump_label_type jump_label_init_type(struct 
jump_entry *entry)
 {
        struct static_key *key = jump_entry_key(entry);
        bool type = static_key_type(key);
-       bool branch = jump_entry_branch(entry);
+       bool branch = jump_entry_is_branch(entry);
 
        /* See the comment in linux/jump_label.h */
        return type ^ branch;
@@ -541,7 +535,7 @@ static int jump_label_add_module(struct module *mod)
                        continue;
 
                key = iterk;
-               if (within_module(iter->key, mod)) {
+               if (within_module((unsigned long)key, mod)) {
                        static_key_set_entries(key, iter);
                        continue;
                }
@@ -591,7 +585,7 @@ static void jump_label_del_module(struct module *mod)
 
                key = jump_entry_key(iter);
 
-               if (within_module(iter->key, mod))
+               if (within_module((unsigned long)key, mod))
                        continue;
 
                /* No memory during module load */
@@ -634,8 +628,8 @@ static void jump_label_invalidate_module_init(struct module 
*mod)
        struct jump_entry *iter;
 
        for (iter = iter_start; iter < iter_stop; iter++) {
-               if (within_module_init(iter->code, mod))
-                       iter->code = 0;
+               if (within_module_init(jump_entry_code(iter), mod))
+                       jump_entry_set_module_init(iter);
        }
 }
 
-- 
2.11.0